fix deprecation messages

Author: alexbarnsley

src/API/Node.php

@@ -53,7 +53,7 @@ public function crypto(): ?array
      *
      * @return array
      */
-    public function fees(int $days = null): ?array
+    public function fees(?int $days = null): ?array
     {
         return $this->get('node/fees', ['days' => $days]);
     }

src/ArkClient.php

@@ -46,7 +46,7 @@ class ArkClient
      *
      * @throws InvalidArgumentException if $hostOrHosts is an array and does not have the required format
      */
-    public function __construct(array|string $hostOrHosts, array $clientConfig = [], HandlerStack $handler = null)
+    public function __construct(array|string $hostOrHosts, array $clientConfig = [], ?HandlerStack $handler = null)
     {
         $this->validateHosts($hostOrHosts);
 

src/ClientManager.php

@@ -49,7 +49,7 @@ public function connect(string $host, string $name = 'main'): ArkClient
      *
      * @param string|null $name
      */
-    public function disconnect(string $name = null): void
+    public function disconnect(?string $name = null): void
     {
         $name = $name ?? $this->getDefaultClient();
 
@@ -63,7 +63,7 @@ public function disconnect(string $name = null): void
      *
      * @return ArkClient
      */
-    public function client(string $name = null): ArkClient
+    public function client(?string $name = null): ArkClient
     {
         $name = $name ?? $this->getDefaultClient();